1
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Burt A, Toader B, Warshamanage R, von Kügelgen A, Pyle E, Zivanov J, Kimanius D, Bharat TAM, Scheres SHW. An image processing pipeline for electron cryo-tomography in RELION-5. FEBS Open Bio 2024. [PMID: 39147729 DOI: 10.1002/2211-5463.13873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/20/2024] [Accepted: 07/16/2024] [Indexed: 08/17/2024] Open
Abstract
Electron tomography of frozen, hydrated samples allows structure determination of macromolecular complexes that are embedded in complex environments. Provided that the target complexes may be localised in noisy, three-dimensional tomographic reconstructions, averaging images of multiple instances of these molecules can lead to structures with sufficient resolution for de novo atomic modelling. Although many research groups have contributed image processing tools for these tasks, a lack of standardisation and interoperability represents a barrier for newcomers to the field. Here, we present an image processing pipeline for electron tomography data in RELION-5, with functionality ranging from the import of unprocessed movies to the automated building of atomic models in the final maps. Our explicit definition of metadata items that describe the steps of our pipeline has been designed for interoperability with other software tools and provides a framework for further standardisation.
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Affiliation(s)
- Alister Burt
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
- Department of Structural Biology, Genentech, South San Francisco, CA, USA
| | - Bogdan Toader
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Rangana Warshamanage
- CCP-EM, Scientific Computing Department, UKRI Science and Technology Facilities Council, Harwell Campus, Didcot, UK
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Euan Pyle
- Institute of Structural and Molecular Biology, Birkbeck College, London, UK
- The Francis Crick Institute, London, UK
| | - Jasenko Zivanov
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Dari Kimanius
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Tanmay A M Bharat
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Sjors H W Scheres
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
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2
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Ruehle MD, Li S, Agard DA, Pearson CG. Poc1 bridges basal body inner junctions to promote triplet microtubule integrity and connections. J Cell Biol 2024; 223:e202311104. [PMID: 38743010 PMCID: PMC11094743 DOI: 10.1083/jcb.202311104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 03/15/2024] [Accepted: 04/09/2024] [Indexed: 05/16/2024] Open
Abstract
Basal bodies (BBs) are conserved eukaryotic structures that organize cilia. They are comprised of nine, cylindrically arranged, triplet microtubules (TMTs) connected to each other by inter-TMT linkages which stabilize the structure. Poc1 is a conserved protein important for BB structural integrity in the face of ciliary forces transmitted to BBs. To understand how Poc1 confers BB stability, we identified the precise position of Poc1 in the Tetrahymena BB and the effect of Poc1 loss on BB structure. Poc1 binds at the TMT inner junctions, stabilizing TMTs directly. From this location, Poc1 also stabilizes inter-TMT linkages throughout the BB, including the cartwheel pinhead and the inner scaffold. The full localization of the inner scaffold protein Fam161A requires Poc1. As ciliary forces are increased, Fam161A is reduced, indicative of a force-dependent molecular remodeling of the inner scaffold. Thus, while not essential for BB assembly, Poc1 promotes BB interconnections that establish an architecture competent to resist ciliary forces.
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Affiliation(s)
- Marisa D. Ruehle
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Sam Li
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - David A. Agard
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Institute for Advanced Biological Imaging, Redwood Shores, CA, USA
| | - Chad G. Pearson
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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3
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Herdman M, Isbilir B, von Kügelgen A, Schulze U, Wainman A, Bharat TAM. Cell cycle dependent coordination of surface layer biogenesis in Caulobacter crescentus. Nat Commun 2024; 15:3355. [PMID: 38637514 PMCID: PMC11026435 DOI: 10.1038/s41467-024-47529-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 04/04/2024] [Indexed: 04/20/2024] Open
Abstract
Surface layers (S-layers) are proteinaceous, two-dimensional paracrystalline arrays that constitute a major component of the cell envelope in many prokaryotic species. In this study, we investigated S-layer biogenesis in the bacterial model organism Caulobacter crescentus. Fluorescence microscopy revealed localised incorporation of new S-layer at the poles and mid-cell, consistent with regions of cell growth in the cell cycle. Light microscopy and electron cryotomography investigations of drug-treated bacteria revealed that localised S-layer insertion is retained when cell division is inhibited, but is disrupted upon dysregulation of MreB or lipopolysaccharide. We further uncovered that S-layer biogenesis follows new peptidoglycan synthesis and localises to regions of high cell wall turnover. Finally, correlated cryo-light microscopy and electron cryotomographic analysis of regions of S-layer insertion showed the presence of discontinuities in the hexagonal S-layer lattice, contrasting with other S-layers completed by defined symmetric defects. Our findings present insights into how C. crescentus cells form an ordered S-layer on their surface in coordination with the biogenesis of other cell envelope components.
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Affiliation(s)
- Matthew Herdman
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Buse Isbilir
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Andriko von Kügelgen
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Ulrike Schulze
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Alan Wainman
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Tanmay A M Bharat
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK.
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4
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Buckley G, Ramm G, Trépout S. GoldDigger and Checkers, computational developments in cryo-scanning transmission electron tomography to improve the quality of reconstructed volumes. BIOLOGICAL IMAGING 2024; 4:e6. [PMID: 38617998 PMCID: PMC11016363 DOI: 10.1017/s2633903x24000047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 04/16/2024]
Abstract
In this work, we present a pair of tools to improve the fiducial tracking and reconstruction quality of cryo-scanning transmission electron tomography (STET) datasets. We then demonstrate the effectiveness of these two tools on experimental cryo-STET data. The first tool, GoldDigger, improves the tracking of fiducials in cryo-STET by accommodating the changed appearance of highly defocussed fiducial markers. Since defocus effects are much stronger in scanning transmission electron microscopy than in conventional transmission electron microscopy, existing alignment tools do not perform well without manual intervention. The second tool, Checkers, combines image inpainting and unsupervised deep learning for denoising tomograms. Existing tools for denoising cryo-tomography often rely on paired noisy image frames, which are unavailable in cryo-STET datasets, necessitating a new approach. Finally, we make the two software tools freely available for the cryo-STET community.
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Affiliation(s)
- Genevieve Buckley
- Ramaciotti Centre for Cryo-EM, Monash University, Clayton, VIC, Australia
| | - Georg Ramm
- Ramaciotti Centre for Cryo-EM, Monash University, Clayton, VIC, Australia
| | - Sylvain Trépout
- Ramaciotti Centre for Cryo-EM, Monash University, Clayton, VIC, Australia
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5
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Liu G, Niu T, Qiu M, Zhu Y, Sun F, Yang G. DeepETPicker: Fast and accurate 3D particle picking for cryo-electron tomography using weakly supervised deep learning. Nat Commun 2024; 15:2090. [PMID: 38453943 PMCID: PMC11258139 DOI: 10.1038/s41467-024-46041-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/12/2024] [Indexed: 03/09/2024] Open
Abstract
To solve three-dimensional structures of biological macromolecules in situ, large numbers of particles often need to be picked from cryo-electron tomograms. However, adoption of automated particle-picking methods remains limited because of their technical limitations. To overcome the limitations, we develop DeepETPicker, a deep learning model for fast and accurate picking of particles from cryo-electron tomograms. Training of DeepETPicker requires only weak supervision with low numbers of simplified labels, reducing the burden of manual annotation. The simplified labels combined with the customized and lightweight model architecture of DeepETPicker and accelerated pooling enable substantial performance improvement. When tested on simulated and real tomograms, DeepETPicker outperforms the competing state-of-the-art methods by achieving the highest overall accuracy and speed, which translate into higher authenticity and coordinates accuracy of picked particles and higher resolutions of final reconstruction maps. DeepETPicker is provided in open source with a user-friendly interface to support cryo-electron tomography in situ.
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Affiliation(s)
- Guole Liu
- State Key Laboratory of Multimodal Artificial Intelligence Systems, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China
- School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tongxin Niu
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Mengxuan Qiu
- State Key Laboratory of Multimodal Artificial Intelligence Systems, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China
- School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yun Zhu
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Fei Sun
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
- School of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, Guangdong, 510005, China.
| | - Ge Yang
- State Key Laboratory of Multimodal Artificial Intelligence Systems, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China.
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing, 100049, China.
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6
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de Isidro-Gómez FP, Vilas JL, Losana P, Carazo JM, Sorzano COS. A deep learning approach to the automatic detection of alignment errors in cryo-electron tomographic reconstructions. J Struct Biol 2024; 216:108056. [PMID: 38101554 DOI: 10.1016/j.jsb.2023.108056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/21/2023] [Accepted: 12/11/2023] [Indexed: 12/17/2023]
Abstract
Electron tomography is an imaging technique that allows for the elucidation of three-dimensional structural information of biological specimens in a very general context, including cellular in situ observations. The approach starts by collecting a set of images at different projection directions by tilting the specimen stage inside the microscope. Therefore, a crucial preliminary step is to precisely define the acquisition geometry by aligning all the tilt images to a common reference. Errors introduced in this step will lead to the appearance of artifacts in the tomographic reconstruction, rendering them unsuitable for the sample study. Focusing on fiducial-based acquisition strategies, this work proposes a deep-learning algorithm to detect misalignment artifacts in tomographic reconstructions by analyzing the characteristics of these fiducial markers in the tomogram. In addition, we propose an algorithm designed to detect fiducial markers in the tomogram with which to feed the classification algorithm in case the alignment algorithm does not provide the location of the markers. This open-source software is available as part of the Xmipp software package inside of the Scipion framework, and also through the command-line in the standalone version of Xmipp.
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Affiliation(s)
- F P de Isidro-Gómez
- Biocomputing Unit, Centro Nacional de Biotecnologia (CNB-CSIC), Darwin, 3, Campus Universidad Autonoma, 28049 Cantoblanco, Madrid, Spain; Univ. Autonoma de Madrid, 28049 Cantoblanco, Madrid, Spain
| | - J L Vilas
- Biocomputing Unit, Centro Nacional de Biotecnologia (CNB-CSIC), Darwin, 3, Campus Universidad Autonoma, 28049 Cantoblanco, Madrid, Spain
| | - P Losana
- Biocomputing Unit, Centro Nacional de Biotecnologia (CNB-CSIC), Darwin, 3, Campus Universidad Autonoma, 28049 Cantoblanco, Madrid, Spain
| | - J M Carazo
- Biocomputing Unit, Centro Nacional de Biotecnologia (CNB-CSIC), Darwin, 3, Campus Universidad Autonoma, 28049 Cantoblanco, Madrid, Spain
| | - C O S Sorzano
- Biocomputing Unit, Centro Nacional de Biotecnologia (CNB-CSIC), Darwin, 3, Campus Universidad Autonoma, 28049 Cantoblanco, Madrid, Spain.
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7
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Ruehle MD, Li S, Agard DA, Pearson CG. Poc1 is a basal body inner junction protein that promotes triplet microtubule integrity and interconnections. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.17.567593. [PMID: 38014135 PMCID: PMC10680851 DOI: 10.1101/2023.11.17.567593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Basal bodies (BBs) are conserved eukaryotic structures that organize motile and primary cilia. The BB is comprised of nine, cylindrically arranged, triplet microtubules (TMTs) that are connected to each other by inter-TMT linkages which maintain BB structure. During ciliary beating, forces transmitted to the BB must be resisted to prevent BB disassembly. Poc1 is a conserved BB protein important for BBs to resist ciliary forces. To understand how Poc1 confers BB stability, we identified the precise position of Poc1 binding in the Tetrahymena BB and the effect of Poc1 loss on BB structure. Poc1 binds at the TMT inner junctions, stabilizing TMTs directly. From this location, Poc1 also stabilizes inter-TMT linkages throughout the BB, including the cartwheel pinhead and the inner scaffold. Moreover, we identify a molecular response to ciliary forces via a molecular remodeling of the inner scaffold, as determined by differences in Fam161A localization. Thus, while not essential for BB assembly, Poc1 promotes BB interconnections that establish an architecture competent to resist ciliary forces.
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Affiliation(s)
- Marisa D. Ruehle
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Sam Li
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - David A. Agard
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Institute for Advanced Biological Imaging, 3400 Bridge Parkway, Redwood Shores, CA, USA
| | - Chad G. Pearson
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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8
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Chen Z, Shiozaki M, Haas KM, Skinner WM, Zhao S, Guo C, Polacco BJ, Yu Z, Krogan NJ, Lishko PV, Kaake RM, Vale RD, Agard DA. De novo protein identification in mammalian sperm using in situ cryoelectron tomography and AlphaFold2 docking. Cell 2023; 186:5041-5053.e19. [PMID: 37865089 PMCID: PMC10842264 DOI: 10.1016/j.cell.2023.09.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 08/02/2023] [Accepted: 09/16/2023] [Indexed: 10/23/2023]
Abstract
To understand the molecular mechanisms of cellular pathways, contemporary workflows typically require multiple techniques to identify proteins, track their localization, and determine their structures in vitro. Here, we combined cellular cryoelectron tomography (cryo-ET) and AlphaFold2 modeling to address these questions and understand how mammalian sperm are built in situ. Our cellular cryo-ET and subtomogram averaging provided 6.0-Å reconstructions of axonemal microtubule structures. The well-resolved tertiary structures allowed us to unbiasedly match sperm-specific densities with 21,615 AlphaFold2-predicted protein models of the mouse proteome. We identified Tektin 5, CCDC105, and SPACA9 as novel microtubule-associated proteins. These proteins form an extensive interaction network crosslinking the lumen of axonemal doublet microtubules, suggesting their roles in modulating the mechanical properties of the filaments. Indeed, Tekt5 -/- sperm possess more deformed flagella with 180° bends. Together, our studies presented a cellular visual proteomics workflow and shed light on the in vivo functions of Tektin 5.
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Affiliation(s)
- Zhen Chen
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA.
| | - Momoko Shiozaki
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Kelsey M Haas
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA; J. David Gladstone Institutes, San Francisco, CA, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA, USA
| | - Will M Skinner
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Shumei Zhao
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Caiying Guo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Benjamin J Polacco
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA, USA
| | - Zhiheng Yu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA; J. David Gladstone Institutes, San Francisco, CA, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA, USA
| | - Polina V Lishko
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Robyn M Kaake
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA; J. David Gladstone Institutes, San Francisco, CA, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA, USA
| | - Ronald D Vale
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
| | - David A Agard
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA, USA.
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9
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Zhao C, Lu D, Zhao Q, Ren C, Zhang H, Zhai J, Gou J, Zhu S, Zhang Y, Gong X. Computational methods for in situ structural studies with cryogenic electron tomography. Front Cell Infect Microbiol 2023; 13:1135013. [PMID: 37868346 PMCID: PMC10586593 DOI: 10.3389/fcimb.2023.1135013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 08/29/2023] [Indexed: 10/24/2023] Open
Abstract
Cryo-electron tomography (cryo-ET) plays a critical role in imaging microorganisms in situ in terms of further analyzing the working mechanisms of viruses and drug exploitation, among others. A data processing workflow for cryo-ET has been developed to reconstruct three-dimensional density maps and further build atomic models from a tilt series of two-dimensional projections. Low signal-to-noise ratio (SNR) and missing wedge are two major factors that make the reconstruction procedure challenging. Because only few near-atomic resolution structures have been reconstructed in cryo-ET, there is still much room to design new approaches to improve universal reconstruction resolutions. This review summarizes classical mathematical models and deep learning methods among general reconstruction steps. Moreover, we also discuss current limitations and prospects. This review can provide software and methods for each step of the entire procedure from tilt series by cryo-ET to 3D atomic structures. In addition, it can also help more experts in various fields comprehend a recent research trend in cryo-ET. Furthermore, we hope that more researchers can collaborate in developing computational methods and mathematical models for high-resolution three-dimensional structures from cryo-ET datasets.
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Affiliation(s)
- Cuicui Zhao
- Mathematical Intelligence Application LAB, Institute for Mathematical Sciences, Renmin University of China, Beijing, China
| | - Da Lu
- Mathematical Intelligence Application LAB, Institute for Mathematical Sciences, Renmin University of China, Beijing, China
| | - Qian Zhao
- Mathematical Intelligence Application LAB, Institute for Mathematical Sciences, Renmin University of China, Beijing, China
| | - Chongjiao Ren
- Mathematical Intelligence Application LAB, Institute for Mathematical Sciences, Renmin University of China, Beijing, China
| | - Huangtao Zhang
- Mathematical Intelligence Application LAB, Institute for Mathematical Sciences, Renmin University of China, Beijing, China
| | - Jiaqi Zhai
- Mathematical Intelligence Application LAB, Institute for Mathematical Sciences, Renmin University of China, Beijing, China
| | - Jiaxin Gou
- Mathematical Intelligence Application LAB, Institute for Mathematical Sciences, Renmin University of China, Beijing, China
| | - Shilin Zhu
- Mathematical Intelligence Application LAB, Institute for Mathematical Sciences, Renmin University of China, Beijing, China
| | - Yaqi Zhang
- Mathematical Intelligence Application LAB, Institute for Mathematical Sciences, Renmin University of China, Beijing, China
| | - Xinqi Gong
- Mathematical Intelligence Application LAB, Institute for Mathematical Sciences, Renmin University of China, Beijing, China
- Beijing Academy of Intelligence, Beijing, China
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10
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Chaillet ML, van der Schot G, Gubins I, Roet S, Veltkamp RC, Förster F. Extensive Angular Sampling Enables the Sensitive Localization of Macromolecules in Electron Tomograms. Int J Mol Sci 2023; 24:13375. [PMID: 37686180 PMCID: PMC10487639 DOI: 10.3390/ijms241713375] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/10/2023] Open
Abstract
Cryo-electron tomography provides 3D images of macromolecules in their cellular context. To detect macromolecules in tomograms, template matching (TM) is often used, which uses 3D models that are often reliable for substantial parts of the macromolecules. However, the extent of rotational searches in particle detection has not been investigated due to computational limitations. Here, we provide a GPU implementation of TM as part of the PyTOM software package, which drastically speeds up the orientational search and allows for sampling beyond the Crowther criterion within a feasible timeframe. We quantify the improvements in sensitivity and false-discovery rate for the examples of ribosome identification and detection. Sampling at the Crowther criterion, which was effectively impossible with CPU implementations due to the extensive computation times, allows for automated extraction with high sensitivity. Consequently, we also show that an extensive angular sample renders 3D TM sensitive to the local alignment of tilt series and damage induced by focused ion beam milling. With this new release of PyTOM, we focused on integration with other software packages that support more refined subtomogram-averaging workflows. The automated classification of ribosomes by TM with appropriate angular sampling on locally corrected tomograms has a sufficiently low false-discovery rate, allowing for it to be directly used for high-resolution averaging and adequate sensitivity to reveal polysome organization.
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Affiliation(s)
- Marten L. Chaillet
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, The Netherlands; (M.L.C.); (G.v.d.S.); (S.R.)
| | - Gijs van der Schot
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, The Netherlands; (M.L.C.); (G.v.d.S.); (S.R.)
| | - Ilja Gubins
- Department of Information and Computing Sciences, Utrecht University, 3584 CC Utrecht, The Netherlands; (I.G.); (R.C.V.)
| | - Sander Roet
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, The Netherlands; (M.L.C.); (G.v.d.S.); (S.R.)
| | - Remco C. Veltkamp
- Department of Information and Computing Sciences, Utrecht University, 3584 CC Utrecht, The Netherlands; (I.G.); (R.C.V.)
| | - Friedrich Förster
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, The Netherlands; (M.L.C.); (G.v.d.S.); (S.R.)
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11
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Böhning J, Dobbelstein AW, Sulkowski N, Eilers K, von Kügelgen A, Tarafder AK, Peak-Chew SY, Skehel M, Alva V, Filloux A, Bharat TAM. Architecture of the biofilm-associated archaic Chaperone-Usher pilus CupE from Pseudomonas aeruginosa. PLoS Pathog 2023; 19:e1011177. [PMID: 37058467 PMCID: PMC10104325 DOI: 10.1371/journal.ppat.1011177] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 02/03/2023] [Indexed: 04/15/2023] Open
Abstract
Chaperone-Usher Pathway (CUP) pili are major adhesins in Gram-negative bacteria, mediating bacterial adherence to biotic and abiotic surfaces. While classical CUP pili have been extensively characterized, little is known about so-called archaic CUP pili, which are phylogenetically widespread and promote biofilm formation by several human pathogens. In this study, we present the electron cryomicroscopy structure of the archaic CupE pilus from the opportunistic human pathogen Pseudomonas aeruginosa. We show that CupE1 subunits within the pilus are arranged in a zigzag architecture, containing an N-terminal donor β-strand extending from each subunit into the next, where it is anchored by hydrophobic interactions, with comparatively weaker interactions at the rest of the inter-subunit interface. Imaging CupE pili on the surface of P. aeruginosa cells using electron cryotomography shows that CupE pili adopt variable curvatures in response to their environment, which might facilitate their role in promoting cellular attachment. Finally, bioinformatic analysis shows the widespread abundance of cupE genes in isolates of P. aeruginosa and the co-occurrence of cupE with other cup clusters, suggesting interdependence of cup pili in regulating bacterial adherence within biofilms. Taken together, our study provides insights into the architecture of archaic CUP pili, providing a structural basis for understanding their role in promoting cellular adhesion and biofilm formation in P. aeruginosa.
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Affiliation(s)
- Jan Böhning
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Adrian W. Dobbelstein
- Department of Protein Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Nina Sulkowski
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Kira Eilers
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Andriko von Kügelgen
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Abul K. Tarafder
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Sew-Yeu Peak-Chew
- Cell Biology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Mark Skehel
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Vikram Alva
- Department of Protein Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Alain Filloux
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Tanmay A. M. Bharat
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
- Structural Studies Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
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12
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Seifer S, Elbaum M. ClusterAlign: A fiducial tracking and tilt series alignment tool for thick sample tomography. BIOLOGICAL IMAGING 2022; 2:e7. [PMID: 38486831 PMCID: PMC10936405 DOI: 10.1017/s2633903x22000071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 07/04/2022] [Accepted: 07/18/2022] [Indexed: 03/17/2024]
Abstract
Thick specimens, as encountered in cryo-scanning transmission electron tomography, offer special challenges to conventional reconstruction workflows. The visibility of features, including gold nanoparticles introduced as fiducial markers, varies strongly through the tilt series. As a result, tedious manual refinement may be required in order to produce a successful alignment. Information from highly tilted views must often be excluded to the detriment of axial resolution in the reconstruction. We introduce here an approach to tilt series alignment based on identification of fiducial particle clusters that transform coherently in rotation, essentially those that lie at similar depth. Clusters are identified by comparison of tilted views with a single untilted reference, rather than with adjacent tilts. The software, called ClusterAlign, proves robust to poor signal to noise ratio and varying visibility of the individual fiducials and is successful in carrying the alignment to the ends of the tilt series where other methods tend to fail. ClusterAlign may be used to generate a list of tracked fiducials, to align a tilt series, or to perform a complete 3D reconstruction. Tools to evaluate alignment error by projection matching are included. Execution involves no manual intervention, and adherence to standard file formats facilitates an interface with other software, particularly IMOD/etomo, tomo3d, and tomoalign.
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Affiliation(s)
- Shahar Seifer
- Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Michael Elbaum
- Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
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13
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Jiménez de la Morena J, Conesa P, Fonseca YC, de Isidro-Gómez FP, Herreros D, Fernández-Giménez E, Strelak D, Moebel E, Buchholz TO, Jug F, Martinez-Sanchez A, Harastani M, Jonic S, Conesa JJ, Cuervo A, Losana P, Sánchez I, Iceta M, Del Cano L, Gragera M, Melero R, Sharov G, Castaño-Díez D, Koster A, Piccirillo JG, Vilas JL, Otón J, Marabini R, Sorzano COS, Carazo JM. ScipionTomo: Towards cryo-electron tomography software integration, reproducibility, and validation. J Struct Biol 2022; 214:107872. [PMID: 35660516 PMCID: PMC7613607 DOI: 10.1016/j.jsb.2022.107872] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/26/2022] [Accepted: 05/28/2022] [Indexed: 11/25/2022]
Abstract
Image processing in cryogenic electron tomography (cryoET) is currently at a similar state as Single Particle Analysis (SPA) in cryogenic electron microscopy (cryoEM) was a few years ago. Its data processing workflows are far from being well defined and the user experience is still not smooth. Moreover, file formats of different software packages and their associated metadata are not standardized, mainly since different packages are developed by different groups, focusing on different steps of the data processing pipeline. The Scipion framework, originally developed for SPA (de la Rosa-Trevín et al., 2016), has a generic python workflow engine that gives it the versatility to be extended to other fields, as demonstrated for model building (Martínez et al., 2020). In this article, we provide an extension of Scipion based on a set of tomography plugins (referred to as ScipionTomo hereafter), with a similar purpose: to allow users to be focused on the data processing and analysis instead of having to deal with multiple software installation issues and the inconvenience of switching from one to another, converting metadata files, managing possible incompatibilities, scripting (writing a simple program in a language that the computer must convert to machine language each time the program is run), etcetera. Additionally, having all the software available in an integrated platform allows comparing the results of different algorithms trying to solve the same problem. In this way, the commonalities and differences between estimated parameters shed light on which results can be more trusted than others. ScipionTomo is developed by a collaborative multidisciplinary team composed of Scipion team engineers, structural biologists, and in some cases, the developers whose software packages have been integrated. It is open to anyone in the field willing to contribute to this project. The result is a framework extension that combines the acquired knowledge of Scipion developers in close collaboration with third-party developers, and the on-demand design of functionalities requested by beta testers applying this solution to actual biological problems.
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Affiliation(s)
| | - P Conesa
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | - Y C Fonseca
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | | | - D Herreros
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | | | - D Strelak
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain; Masaryk University, Brno, Czech Republic
| | - E Moebel
- Inria Rennes - Bretagne Atlantique, Rennes
| | - T O Buchholz
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Germany; Center for Systems Biology Dresden (CSBD), Germany
| | - F Jug
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Germany; Fondazione Human Technopole, Milan, Italy
| | - A Martinez-Sanchez
- University of Oviedo, Department of Computer Sciences, Oviedo, Spain; Health Research Institute of Asturias (ISPA), Oviedo, Spain
| | - M Harastani
- IMPMC-UMR 7590 CNRS, Sorbonne Université, MNHN, Paris, France
| | - S Jonic
- IMPMC-UMR 7590 CNRS, Sorbonne Université, MNHN, Paris, France
| | - J J Conesa
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | - A Cuervo
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | - P Losana
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | - I Sánchez
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | - M Iceta
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | - L Del Cano
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | - M Gragera
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | - R Melero
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | - G Sharov
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - D Castaño-Díez
- BioEM Lab, Biozentrum, University of Basel, Basel, Switzerland
| | - A Koster
- University of Leiden, Ultrastructural and molecular imaging, Leiden, The Netherlands
| | - J G Piccirillo
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | - J L Vilas
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | - J Otón
- Alba Synchrotron - CELLS (ICTS), Barcelona, Spain
| | - R Marabini
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain; Superior Polytechnic School. Univ. Autónoma of Madrid. Madrid, Spain
| | - C O S Sorzano
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
| | - J M Carazo
- National Center of Biotechnology (CNB-CSIC), Madrid, Spain
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14
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Zheng S, Wolff G, Greenan G, Chen Z, Faas FGA, Bárcena M, Koster AJ, Cheng Y, Agard DA. AreTomo: An integrated software package for automated marker-free, motion-corrected cryo-electron tomographic alignment and reconstruction. J Struct Biol X 2022; 6:100068. [PMID: 35601683 PMCID: PMC9117686 DOI: 10.1016/j.yjsbx.2022.100068] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/02/2022] [Indexed: 11/28/2022] Open
Abstract
AreTomo, a GPU accelerated software package, fully automates motion-corrected marker-free tomographic alignment and reconstruction. AreTomo can produce tomograms with sufficient accuracy to be directly used for subtomogram averaging. AreTomo enables the on-the-fly reconstruction of tomograms in parallel with tilt series collection, thus providing users with real-time feedback of sample quality.
AreTomo, an abbreviation for Alignment and Reconstruction for Electron Tomography, is a GPU accelerated software package that fully automates motion-corrected marker-free tomographic alignment and reconstruction in a single package. By correcting in-plane rotation, translation, and importantly, the local motion resulting from beam-induced motion from tilt to tilt, AreTomo can produce tomograms with sufficient accuracy to be directly used for subtomogram averaging. Another major application is the on-the-fly reconstruction of tomograms in parallel with tilt series collection to provide users with real-time feedback of sample quality allowing users to make any necessary adjustments of collection parameters. Here, the multiple alignment algorithms implemented in AreTomo are described and the local motions measured on a typical tilt series are analyzed. The residual local motion after correction for global motion was found in the range of ± 80 Å, indicating that the accurate correction of local motion is critical for high-resolution cryo-electron tomography (cryoET).
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Affiliation(s)
- Shawn Zheng
- Dept. Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA
- Howard Hughes Medical Institute, USA
| | - Georg Wolff
- Section Electron Microscopy, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden 2333 ZC, Netherlands
| | - Garrett Greenan
- Dept. Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA
| | - Zhen Chen
- Dept. Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA
| | - Frank G A Faas
- Section Electron Microscopy, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden 2333 ZC, Netherlands
| | - Montserrat Bárcena
- Section Electron Microscopy, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden 2333 ZC, Netherlands
| | - Abraham J Koster
- Section Electron Microscopy, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden 2333 ZC, Netherlands
| | - Yifan Cheng
- Dept. Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA
- Howard Hughes Medical Institute, USA
| | - David A Agard
- Dept. Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA
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15
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Krause S, Gfrerer S, von Kügelgen A, Reuse C, Dombrowski N, Villanueva L, Bunk B, Spröer C, Neu TR, Kuhlicke U, Schmidt-Hohagen K, Hiller K, Bharat TAM, Rachel R, Spang A, Gescher J. The importance of biofilm formation for cultivation of a Micrarchaeon and its interactions with its Thermoplasmatales host. Nat Commun 2022; 13:1735. [PMID: 35365607 PMCID: PMC8975820 DOI: 10.1038/s41467-022-29263-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 02/28/2022] [Indexed: 01/05/2023] Open
Abstract
Micrarchaeota is a distinctive lineage assigned to the DPANN archaea, which includes poorly characterised microorganisms with reduced genomes that likely depend on interactions with hosts for growth and survival. Here, we report the enrichment of a stable co-culture of a member of the Micrarchaeota (Ca. Micrarchaeum harzensis) together with its Thermoplasmatales host (Ca. Scheffleriplasma hospitalis), as well as the isolation of the latter. We show that symbiont-host interactions depend on biofilm formation as evidenced by growth experiments, comparative transcriptomic analyses and electron microscopy. In addition, genomic, metabolomic, extracellular polymeric substances and lipid content analyses indicate that the Micrarchaeon symbiont relies on the acquisition of metabolites from its host. Our study of the cell biology and physiology of a Micrarchaeon and its host adds to our limited knowledge of archaeal symbioses. The Micrarchaeota lineage includes poorly characterized archaea with reduced genomes that likely depend on host interactions for survival. Here, the authors report a stable co-culture of a member of the Micrarchaeota and its host, and use multi-omic and physiological analyses to shed light on this symbiosis.
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Affiliation(s)
- Susanne Krause
- Department of Applied Biology, Karlsruhe, Institute of Technology (KIT), Karlsruhe, Germany
| | - Sabrina Gfrerer
- Department of Applied Biology, Karlsruhe, Institute of Technology (KIT), Karlsruhe, Germany.,Institute for Biological Interfaces, Karlsruhe, Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Andriko von Kügelgen
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, United Kingdom
| | - Carsten Reuse
- Bioinformatics & Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre for Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Nina Dombrowski
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands
| | - Laura Villanueva
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands.,Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Boyke Bunk
- Leibniz Institute DSMZ, Braunschweig, Germany
| | | | - Thomas R Neu
- Helmholtz-Centre for Environmental, Research UFZ, Magdeburg, Germany
| | - Ute Kuhlicke
- Helmholtz-Centre for Environmental, Research UFZ, Magdeburg, Germany
| | - Kerstin Schmidt-Hohagen
- Bioinformatics & Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre for Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Karsten Hiller
- Bioinformatics & Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre for Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Tanmay A M Bharat
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, United Kingdom.,Structural Studies Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, United Kingdom
| | - Reinhard Rachel
- Center for Electron Microscopy, University of Regensburg, Regensburg, Germany
| | - Anja Spang
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands.,Department of Cell- and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Johannes Gescher
- Department of Applied Biology, Karlsruhe, Institute of Technology (KIT), Karlsruhe, Germany. .,Institute for Biological Interfaces, Karlsruhe, Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany. .,Institute of Technical Microbiology, Technical University of Hamburg, Hamburg, Germany.
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16
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Calcraft T, Rosenthal PB. Cryogenic electron microscopy approaches that combine images and tilt series. Microscopy (Oxf) 2022; 71:i15-i22. [PMID: 35275182 PMCID: PMC8855521 DOI: 10.1093/jmicro/dfab053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/29/2021] [Accepted: 01/28/2022] [Indexed: 11/12/2022] Open
Abstract
Cryogenic electron microscopy can be widely applied to biological specimens from the molecular to the cellular scale. In single-particle analysis, 3D structures may be obtained in high resolution by averaging 2D images of single particles in random orientations. For pleomorphic specimens, structures may be obtained by recording the tilt series of a single example of the specimen and calculating tomograms. Where many copies of a single structure such as a protein or nucleic acid assembly are present within the tomogram, averaging of the sub-volumes (subtomogram averaging) has been successfully applied. The choice of data collection method for any given specimen may depend on the structural question of interest and is determined by the radiation sensitivity of the specimen. Here, we survey some recent developments on the use of hybrid methods for recording and analysing data from radiation-sensitive biological specimens. These include single-particle reconstruction from 2D images where additional views are recorded at a single tilt angle of the specimen and methods where image tilt series, initially used for tomogram reconstruction, are processed as individual single-particle images. There is a continuum of approaches now available to maximize structural information obtained from the specimen.
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Affiliation(s)
- Thomas Calcraft
- Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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17
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Li S, Fernandez JJ, Fabritius AS, Agard DA, Winey M. Electron cryo-tomography structure of axonemal doublet microtubule from Tetrahymena thermophila. Life Sci Alliance 2022; 5:5/3/e202101225. [PMID: 34969817 PMCID: PMC8742875 DOI: 10.26508/lsa.202101225] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 11/24/2022] Open
Abstract
Doublet microtubules (DMTs) provide a scaffold for axoneme assembly in motile cilia. Aside from α/β tubulins, the DMT comprises a large number of non-tubulin proteins in the luminal wall of DMTs, collectively named the microtubule inner proteins (MIPs). We used cryoET to study axoneme DMT isolated from Tetrahymena We present the structures of DMT at nanometer and sub-nanometer resolution. The structures confirm that MIP RIB72A/B binds to the luminal wall of DMT by multiple DM10 domains. We found FAP115, an MIP-containing multiple EF-hand domains, located at the interface of four-tubulin dimers in the lumen of A-tubule. It contacts both lateral and longitudinal tubulin interfaces and playing a critical role in DMT stability. We observed substantial structure heterogeneity in DMT in an FAP115 knockout strain, showing extensive structural defects beyond the FAP115-binding site. The defects propagate along the axoneme. Finally, by comparing DMT structures from Tetrahymena and Chlamydomonas, we have identified a number of conserved MIPs as well as MIPs that are unique to each organism. This conservation and diversity of the DMT structures might be linked to their specific functions. Our work provides structural insights essential for understanding the roles of MIPs during motile cilium assembly and function, as well as their relationships to human ciliopathies.
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Affiliation(s)
- Sam Li
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
| | - Jose-Jesus Fernandez
- Nanomaterials and Nanotechnology Research Center (CINN-CSIC), Health Research Institute of Asturias (ISPA), Oviedo, Spain
| | - Amy S Fabritius
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA, USA
| | - David A Agard
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
| | - Mark Winey
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA, USA
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18
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Herdman M, von Kügelgen A, Kureisaite-Ciziene D, Duman R, El Omari K, Garman EF, Kjaer A, Kolokouris D, Löwe J, Wagner A, Stansfeld PJ, Bharat TAM. High-resolution mapping of metal ions reveals principles of surface layer assembly in Caulobacter crescentus cells. Structure 2021; 30:215-228.e5. [PMID: 34800371 PMCID: PMC8828063 DOI: 10.1016/j.str.2021.10.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 08/17/2021] [Accepted: 10/22/2021] [Indexed: 12/02/2022]
Abstract
Surface layers (S-layers) are proteinaceous crystalline coats that constitute the outermost component of most prokaryotic cell envelopes. In this study, we have investigated the role of metal ions in the formation of the Caulobacter crescentus S-layer using high-resolution structural and cell biology techniques, as well as molecular simulations. Utilizing optical microscopy of fluorescently tagged S-layers, we show that calcium ions facilitate S-layer lattice formation and cell-surface binding. We report all-atom molecular dynamics simulations of the S-layer lattice, revealing the importance of bound metal ions. Finally, using electron cryomicroscopy and long-wavelength X-ray diffraction experiments, we mapped the positions of metal ions in the S-layer at near-atomic resolution, supporting our insights from the cellular and simulations data. Our findings contribute to the understanding of how C. crescentus cells form a regularly arranged S-layer on their surface, with implications on fundamental S-layer biology and the synthetic biology of self-assembling biomaterials. Live imaging shows Ca2+-dependent expansion of the C. crescentus S-layer Molecular simulations reveal Ca2+-binding properties of the S-layer Ca2+ ion mapping in three-dimensional crystals using in-vacuum X-ray anomalous diffraction Ca2+ replacement by Ho3+ allows cryo-EM mapping of heavy metals
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Affiliation(s)
- Matthew Herdman
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | | | | | - Ramona Duman
- Diamond Light Source, Harwell Science & Innovation Campus, Didcot OX11 0DE, UK
| | - Kamel El Omari
- Diamond Light Source, Harwell Science & Innovation Campus, Didcot OX11 0DE, UK
| | - Elspeth F Garman
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Andreas Kjaer
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | | | - Jan Löwe
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Armin Wagner
- Diamond Light Source, Harwell Science & Innovation Campus, Didcot OX11 0DE, UK
| | - Phillip J Stansfeld
- School of Life Sciences and Department of Chemistry, Gibbet Hill Campus, University of Warwick, Coventry CV4 7AL, UK.
| | - Tanmay A M Bharat
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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19
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Fabritius AS, Bayless BA, Li S, Stoddard D, Heydeck W, Ebmeier CC, Anderson L, Gunnels T, Nachiappan C, Whittall JB, Old W, Agard DA, Nicastro D, Winey M. Proteomic analysis of microtubule inner proteins (MIPs) in Rib72 null Tetrahymena cells reveals functional MIPs. Mol Biol Cell 2021; 32:br8. [PMID: 34406789 PMCID: PMC8693976 DOI: 10.1091/mbc.e20-12-0786] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The core structure of motile cilia and flagella, the axoneme, is built from a stable population of doublet microtubules. This unique stability is brought about, at least in part, by a network of microtubule inner proteins (MIPs) that are bound to the luminal side of the microtubule walls. Rib72A and Rib72B were identified as MIPs in the motile cilia of the protist Tetrahymena thermophila. Loss of these proteins leads to ciliary defects and loss of additional MIPs. We performed mass spectrometry coupled with proteomic analysis and bioinformatics to identify the MIPs lost in RIB72A/B knockout Tetrahymena axonemes. We identified a number of candidate MIPs and pursued one, Fap115, for functional characterization. We find that loss of Fap115 results in disrupted cell swimming and aberrant ciliary beating. Cryo-electron tomography reveals that Fap115 localizes to MIP6a in the A-tubule of the doublet microtubules. Overall, our results highlight the complex relationship between MIPs, ciliary structure, and ciliary function.
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Affiliation(s)
- Amy S Fabritius
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616
| | - Brian A Bayless
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616.,Department of Biology, Santa Clara University, Santa Clara, CA 95053
| | - Sam Li
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158
| | - Daniel Stoddard
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Westley Heydeck
- Department of Molecular Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309
| | - Christopher C Ebmeier
- Department of Molecular Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309
| | - Lauren Anderson
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616
| | - Tess Gunnels
- Department of Biology, Santa Clara University, Santa Clara, CA 95053
| | | | - Justen B Whittall
- Department of Biology, Santa Clara University, Santa Clara, CA 95053
| | - William Old
- Department of Molecular Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309
| | - David A Agard
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158
| | - Daniela Nicastro
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Mark Winey
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616
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20
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Wensel TG, Potter VL, Moye A, Zhang Z, Robichaux MA. Structure and dynamics of photoreceptor sensory cilia. Pflugers Arch 2021; 473:1517-1537. [PMID: 34050409 PMCID: PMC11216635 DOI: 10.1007/s00424-021-02564-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 02/06/2023]
Abstract
The rod and cone photoreceptor cells of the vertebrate retina have highly specialized structures that enable them to carry out their function of light detection over a broad range of illumination intensities with optimized spatial and temporal resolution. Most prominent are their unusually large sensory cilia, consisting of outer segments packed with photosensitive disc membranes, a connecting cilium with many features reminiscent of the primary cilium transition zone, and a pair of centrioles forming a basal body which serves as the platform upon which the ciliary axoneme is assembled. These structures form a highway through which an enormous flux of material moves on a daily basis to sustain the continual turnover of outer segment discs and the energetic demands of phototransduction. After decades of study, the details of the fine structure and distribution of molecular components of these structures are still incompletely understood, but recent advances in cellular imaging techniques and animal models of inherited ciliary defects are yielding important new insights. This knowledge informs our understanding both of the mechanisms of trafficking and assembly and of the pathophysiological mechanisms of human blinding ciliopathies.
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Affiliation(s)
- Theodore G Wensel
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology and Developmental Biology Graduate Program, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Valencia L Potter
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology and Developmental Biology Graduate Program, Baylor College of Medicine, Houston, TX, 77030, USA
- Medical Scientist Training Program (MSTP), Baylor College of Medicine, Houston, TX, 77030, USA
| | - Abigail Moye
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Zhixian Zhang
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Michael A Robichaux
- Departments of Ophthalmology and Biochemistry, West Virginia University, Morgantown, WV, USA
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21
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TomoAlign: A novel approach to correcting sample motion and 3D CTF in CryoET. J Struct Biol 2021; 213:107778. [PMID: 34416376 DOI: 10.1016/j.jsb.2021.107778] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 07/16/2021] [Accepted: 08/08/2021] [Indexed: 11/23/2022]
Abstract
TomoAlign is a software package that integrates tools to mitigate two important resolution limiting factors in cryoET, namely the beam-induced sample motion and the contrast transfer function (CTF) of the microscope. The package is especially focused on cryoET of thick specimens where fiducial markers are required for accurate tilt-series alignment and sample motion estimation. TomoAlign models the beam-induced sample motion undergone during the tilt-series acquisition. The motion models are used to produce motion-corrected subtilt-series centered on the particles of interest. In addition, the defocus of each particle at each tilt image is determined and can be corrected, resulting in motion-corrected and CTF-corrected subtilt-series from which the subtomograms can be computed. Alternatively, the CTF information can be passed on so that CTF correction can be carried out entirely within external packages like Relion. TomoAlign serves as a versatile tool that can streamline the cryoET workflow from initial alignment of tilt-series to final subtomogram averaging during in situ structure determination.
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22
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Bäuerlein FJB, Baumeister W. Towards Visual Proteomics at High Resolution. J Mol Biol 2021; 433:167187. [PMID: 34384780 DOI: 10.1016/j.jmb.2021.167187] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/02/2021] [Accepted: 08/02/2021] [Indexed: 11/24/2022]
Abstract
Traditionally, structural biologists approach the complexity of cellular proteomes in a reductionist manner. Proteomes are fractionated, their molecular components purified and studied one-by-one using the experimental methods for structure determination at their disposal. Visual proteomics aims at obtaining a holistic picture of cellular proteomes by studying them in situ, ideally in unperturbed cellular environments. The method that enables doing this at highest resolution is cryo-electron tomography. It allows to visualize cellular landscapes with molecular resolution generating maps or atlases revealing the interaction networks which underlie cellular functions in health and in disease states. Current implementations of cryo ET do not yet realize the full potential of the method in terms of resolution and interpretability. To this end, further improvements in technology and methodology are needed. This review describes the state of the art as well as measures which we expect will help overcoming current limitations.
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Affiliation(s)
- Felix J B Bäuerlein
- Max-Planck-Institute of Biochemistry, Department for Molecular Structural Biology, Am Klopferspitz 18, 82152 Planegg, Germany; Georg-August-University, Institute for Neuropathology, Robert-Koch-Strasse 40, 37075 Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.
| | - Wolfgang Baumeister
- Max-Planck-Institute of Biochemistry, Department for Molecular Structural Biology, Am Klopferspitz 18, 82152 Planegg, Germany.
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23
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Architecture of cell-cell junctions in situ reveals a mechanism for bacterial biofilm inhibition. Proc Natl Acad Sci U S A 2021; 118:2109940118. [PMID: 34321357 PMCID: PMC8346871 DOI: 10.1073/pnas.2109940118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Many bacteria, including the major human pathogen Pseudomonas aeruginosa, are naturally found in multicellular, antibiotic-tolerant biofilm communities, in which cells are embedded in an extracellular matrix of polymeric molecules. Cell-cell interactions within P. aeruginosa biofilms are mediated by CdrA, a large, membrane-associated adhesin present in the extracellular matrix of biofilms, regulated by the cytoplasmic concentration of cyclic diguanylate. Here, using electron cryotomography of focused ion beam-milled specimens, we report the architecture of CdrA molecules in the extracellular matrix of P. aeruginosa biofilms at intact cell-cell junctions. Combining our in situ observations at cell-cell junctions with biochemistry, native mass spectrometry, and cellular imaging, we demonstrate that CdrA forms an extended structure that projects from the outer membrane to tether cells together via polysaccharide binding partners. We go on to show the functional importance of CdrA using custom single-domain antibody (nanobody) binders. Nanobodies targeting the tip of functional cell-surface CdrA molecules could be used to inhibit bacterial biofilm formation or disrupt preexisting biofilms in conjunction with bactericidal antibiotics. These results reveal a functional mechanism for cell-cell interactions within bacterial biofilms and highlight the promise of using inhibitors targeting biofilm cell-cell junctions to prevent or treat problematic, chronic bacterial infections.
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24
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Pyle E, Zanetti G. Current data processing strategies for cryo-electron tomography and subtomogram averaging. Biochem J 2021; 478:1827-1845. [PMID: 34003255 PMCID: PMC8133831 DOI: 10.1042/bcj20200715] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/19/2021] [Accepted: 04/26/2021] [Indexed: 12/25/2022]
Abstract
Cryo-electron tomography (cryo-ET) can be used to reconstruct three-dimensional (3D) volumes, or tomograms, from a series of tilted two-dimensional images of biological objects in their near-native states in situ or in vitro. 3D subvolumes, or subtomograms, containing particles of interest can be extracted from tomograms, aligned, and averaged in a process called subtomogram averaging (STA). STA overcomes the low signal to noise ratio within the individual subtomograms to generate structures of the particle(s) of interest. In recent years, cryo-ET with STA has increasingly been capable of reaching subnanometer resolution due to improvements in microscope hardware and data processing strategies. There has also been an increase in the number and quality of software packages available to process cryo-ET data with STA. In this review, we describe and assess the data processing strategies available for cryo-ET data and highlight the recent software developments which have enabled the extraction of high-resolution information from cryo-ET datasets.
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Affiliation(s)
- Euan Pyle
- Institute of Structural and Molecular Biology, Birkbeck College, Malet St., London WC1E 7HX, U.K
| | - Giulia Zanetti
- Institute of Structural and Molecular Biology, Birkbeck College, Malet St., London WC1E 7HX, U.K
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25
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Berger C, Ravelli RBG, López-Iglesias C, Peters PJ. Endocytosed nanogold fiducials for improved in-situ cryo-electron tomography tilt-series alignment. J Struct Biol 2021; 213:107698. [PMID: 33545353 DOI: 10.1016/j.jsb.2021.107698] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/24/2020] [Accepted: 01/13/2021] [Indexed: 11/17/2022]
Abstract
Cryo-electron tomography (CET) on cryo-focused ion beam (FIB)-milled lamellae is becoming a powerful technique for determining the structure of macromolecular complexes in their native cellular environment. Prior to tomogram reconstruction, CET tilt-series recorded on FIB lamellae need to be aligned. Traditionally, CET tilt-series alignment is performed with 5-20 nm gold fiducials, but it has thus far proven difficult to apply this to FIB lamellae of eukaryotic cells. In here, we describe a simple method to allow uptake of bovine serum albumin (BSA)-gold fiducials into mammalian cells via endocytosis, which can subsequently be used as fiducials for tilt-series alignment of cryo-FIB lamellae. We compare the alignment of tilt-series with BSA-gold fiducials to fiducial-less patch-tracking, and find better alignment results with BSA-gold. This technique can contribute to understand cells at a structural and ultrastructural level with both cryo- and room-temperature electron tomography. Furthermore, fluorescently labeled BSA-gold has the potential to be used as fiducials for correlative light and electron microscopy studies.
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Affiliation(s)
- Casper Berger
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, the Netherlands
| | - Raimond B G Ravelli
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, the Netherlands
| | - Carmen López-Iglesias
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, the Netherlands
| | - Peter J Peters
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, the Netherlands.
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26
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Han R, Li G, Gao X. Robust and ultrafast fiducial marker correspondence in electron tomography by a two-stage algorithm considering local constraints. Bioinformatics 2021; 37:107-117. [PMID: 33416867 PMCID: PMC8694346 DOI: 10.1093/bioinformatics/btaa1098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 12/08/2020] [Accepted: 12/28/2020] [Indexed: 11/24/2022] Open
Abstract
Motivation Electron tomography (ET) has become an indispensable tool for structural biology studies. In ET, the tilt series alignment and the projection parameter calibration are the key steps toward high-resolution ultrastructure analysis. Usually, fiducial markers are embedded in the sample to aid the alignment. Despite the advances in developing algorithms to find correspondence of fiducial markers from different tilted micrographs, the error rate of the existing methods is still high such that manual correction has to be conducted. In addition, existing algorithms do not work well when the number of fiducial markers is high. Results In this article, we try to completely solve the fiducial marker correspondence problem. We propose to divide the workflow of fiducial marker correspondence into two stages: (i) initial transformation determination, and (ii) local correspondence refinement. In the first stage, we model the transform estimation as a correspondence pair inquiry and verification problem. The local geometric constraints and invariant features are used to reduce the complexity of the problem. In the second stage, we encode the geometric distribution of the fiducial markers by a weighted Gaussian mixture model and introduce drift parameters to correct the effects of beam-induced motion and sample deformation. Comprehensive experiments on real-world datasets demonstrate the robustness, efficiency and effectiveness of the proposed algorithm. Especially, the proposed two-stage algorithm is able to produce an accurate tracking within an average of ⩽ 100 ms per image, even for micrographs with hundreds of fiducial markers, which makes the real-time ET data processing possible. Availability and implementation The code is available at https://github.com/icthrm/auto-tilt-pair. Additionally, the detailed original figures demonstrated in the experiments can be accessed at https://rb.gy/6adtk4. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Renmin Han
- Research Center for Mathematics and Interdisciplinary Sciences, Shandong University, Qingdao, 266237, PR China.,Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Guojun Li
- Research Center for Mathematics and Interdisciplinary Sciences, Shandong University, Qingdao, 266237, PR China
| | - Xin Gao
- Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
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27
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Abstract
Cryo-electron tomography (cryo-ET) is an extremely powerful tool which is used to image cellular features in their close-to-native environment at a resolution where both protein structure and membrane morphology can be revealed. Compared to conventional electron microscopy methods for biology, cryo-ET does not include the use of potentially artifact generating agents for sample fixation or visualization. Despite its obvious advantages, cryo-ET has not been widely adopted by cell biologists. This might originate from the overwhelming and constantly growing number of complex ways to record and process data as well as the numerous methods available for sample preparation. In this chapter, we will take one step back and guide the reader through the essential steps of sample preparation using mammalian cells, as well as the basic steps involved in data recording and processing. The described protocol will allow the reader to obtain data that can be used for morphological analysis and precise measurements of biological structures in their cellular environment. Furthermore, this data can be used for more elaborate structural analysis by applying further image processing steps like subtomogram averaging, which is required to determine the structure of proteins.
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28
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Bharat TAM, von Kügelgen A, Alva V. Molecular Logic of Prokaryotic Surface Layer Structures. Trends Microbiol 2020; 29:405-415. [PMID: 33121898 PMCID: PMC8559796 DOI: 10.1016/j.tim.2020.09.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/18/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022]
Abstract
Most prokaryotic cells are encased in a surface layer (S-layer) consisting of a paracrystalline array of repeating lattice-forming proteins. S-layer proteins populate a vast and diverse sequence space, performing disparate functions in prokaryotic cells, including cellular defense, cell-shape maintenance, and regulation of import and export of materials. This article highlights recent advances in the understanding of S-layer structure and assembly, made possible by rapidly evolving structural and cell biology methods. We underscore shared assembly principles revealed by recent work and discuss a common molecular framework that may be used to understand the structural organization of S-layer proteins across bacteria and archaea. Despite enormous sequence diversity in surface (S)-layer proteins, structural diversity is much lower than previously thought. S-layer proteins have a bipartite arrangement with a lattice-forming and an anchoring segment. Novel structural biology methods are revealing the architectures of S-layers in situ. S-layer assembly across prokaryotes is tightly coupled to the cell cycle, including the cell division machinery.
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Affiliation(s)
- Tanmay A M Bharat
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; Central Oxford Structural Microscopy and Imaging Centre, University of Oxford, Oxford OX1 3RE, UK.
| | - Andriko von Kügelgen
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; Central Oxford Structural Microscopy and Imaging Centre, University of Oxford, Oxford OX1 3RE, UK
| | - Vikram Alva
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, Tübingen 72076, Germany.
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29
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Turk M, Baumeister W. The promise and the challenges of cryo-electron tomography. FEBS Lett 2020; 594:3243-3261. [PMID: 33020915 DOI: 10.1002/1873-3468.13948] [Citation(s) in RCA: 144] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/28/2020] [Accepted: 09/28/2020] [Indexed: 01/11/2023]
Abstract
Structural biologists have traditionally approached cellular complexity in a reductionist manner in which the cellular molecular components are fractionated and purified before being studied individually. This 'divide and conquer' approach has been highly successful. However, awareness has grown in recent years that biological functions can rarely be attributed to individual macromolecules. Most cellular functions arise from their concerted action, and there is thus a need for methods enabling structural studies performed in situ, ideally in unperturbed cellular environments. Cryo-electron tomography (Cryo-ET) combines the power of 3D molecular-level imaging with the best structural preservation that is physically possible to achieve. Thus, it has a unique potential to reveal the supramolecular architecture or 'molecular sociology' of cells and to discover the unexpected. Here, we review state-of-the-art Cryo-ET workflows, provide examples of biological applications, and discuss what is needed to realize the full potential of Cryo-ET.
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Affiliation(s)
- Martin Turk
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
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30
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Kamyshinsky RA, Chesnokov YM, Orekhov AS. Cryo-Electron Tomography Studies of Cell Systems. CRYSTALLOGR REP+ 2020. [DOI: 10.1134/s1063774520050090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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31
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Han R, Wan X, Li L, Lawrence A, Yang P, Li Y, Wang S, Sun F, Liu Z, Gao X, Zhang F. AuTom-dualx: a toolkit for fully automatic fiducial marker-based alignment of dual-axis tilt series with simultaneous reconstruction. Bioinformatics 2019; 35:319-328. [PMID: 30010792 PMCID: PMC6330008 DOI: 10.1093/bioinformatics/bty620] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 07/11/2018] [Indexed: 11/21/2022] Open
Abstract
Motivation Dual-axis electron tomography is an important 3 D macro-molecular structure reconstruction technology, which can reduce artifacts and suppress the effect of missing wedge. However, the fully automatic data process for dual-axis electron tomography still remains a challenge due to three difficulties: (i) how to track the mass of fiducial markers automatically; (ii) how to integrate the information from the two different tilt series; and (iii) how to cope with the inconsistency between the two different tilt series. Results Here we develop a toolkit for fully automatic alignment of dual-axis electron tomography, with a simultaneous reconstruction procedure. The proposed toolkit and its workflow carries out the following solutions: (i) fully automatic detection and tracking of fiducial markers under large-field datasets; (ii) automatic combination of two different tilt series and global calibration of projection parameters; and (iii) inconsistency correction based on distortion correction parameters and the consequently simultaneous reconstruction. With all of these features, the presented toolkit can achieve accurate alignment and reconstruction simultaneously and conveniently under a single global coordinate system. Availability and implementation The toolkit AuTom-dualx (alignment module dualxmauto and reconstruction module volrec_mltm) are accessible for general application at http://ear.ict.ac.cn, and the key source code is freely available under request. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Renmin Han
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, Thuwal, Saudi Arabia
| | - Xiaohua Wan
- High Performance Computer Research Center, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China
| | - Lun Li
- High Performance Computer Research Center, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Albert Lawrence
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California, San Diego, CA, USA and
| | - Peng Yang
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, Thuwal, Saudi Arabia
| | - Yu Li
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, Thuwal, Saudi Arabia
| | - Sheng Wang
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, Thuwal, Saudi Arabia
| | - Fei Sun
- National Laboratory of Biomacromolecules, Institute of Biophysics Chinese Academy of Sciences, Beijing, China
| | - Zhiyong Liu
- High Performance Computer Research Center, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China
| | - Xin Gao
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, Thuwal, Saudi Arabia
| | - Fa Zhang
- High Performance Computer Research Center, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China
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32
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Abstract
Cryo-electron tomography (cryo-ET) allows three-dimensional (3D) visualization of frozen-hydrated biological samples, such as protein complexes and cell organelles, in near-native environments at nanometer scale. Protein complexes that are present in multiple copies in a set of tomograms can be extracted, mutually aligned, and averaged to yield a signal-enhanced 3D structure up to sub-nanometer or even near-atomic resolution. This technique, called subtomogram averaging (StA), is powered by improvements in EM hardware and image processing software. Importantly, StA provides unique biological insights into the structure and function of cellular machinery in close-to-native contexts. In this chapter, we describe the principles and key steps of StA. We briefly cover sample preparation and data collection with an emphasis on image processing procedures related to tomographic reconstruction, subtomogram alignment, averaging, and classification. We conclude by summarizing current limitations and future directions of this technique with a focus on high-resolution StA.
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33
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Consideration of sample motion in cryo-tomography based on alignment residual interpolation. J Struct Biol 2019; 205:1-6. [PMID: 30690142 DOI: 10.1016/j.jsb.2019.01.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 01/14/2019] [Accepted: 01/16/2019] [Indexed: 11/24/2022]
Abstract
Recently, it has been shown that the resolution in cryo-tomography could be improved by considering the sample motion in tilt-series alignment and reconstruction, where a set of quadratic polynomials were used to model this motion. One requirement of this polynomial method is the optimization of a large number of parameters, which may limit its practical applicability. In this work, we propose an alternative method for modeling the sample motion. Starting from the standard fiducial-based tilt-series alignment, the method uses the alignment residual as local estimates of the sample motion at the 3D fiducial positions. Then, a scattered data interpolation technique characterized by its smoothness and a closed-form solution is applied to model the sample motion. The motion model is then integrated in the tomographic reconstruction. The new method improves the tomogram quality similar to the polynomial one, with the important advantage that the determination of the motion model is greatly simplified, thereby overcoming one of the major limitations of the polynomial model. Therefore, the new method is expected to make the beam-induced motion correction methodology more accessible to the cryoET community.
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34
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Dynamic Tomographic Reconstruction of Deforming Volumes. MATERIALS 2018; 11:ma11081395. [PMID: 30096947 PMCID: PMC6119884 DOI: 10.3390/ma11081395] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/03/2018] [Accepted: 08/06/2018] [Indexed: 12/20/2022]
Abstract
The motion of a sample while being scanned in a tomograph prevents its proper volume reconstruction. In the present study, a procedure is proposed that aims at estimating both the kinematics of the sample and its standard 3D imaging from a standard acquisition protocol (no more projection than for a rigid specimen). The proposed procedure is a staggered two-step algorithm where the volume is first reconstructed using a “Dynamic Reconstruction” technique, a variant of Algebraic Reconstruction Technique (ART) compensating for a “frozen” determination of the motion, followed by a Projection-based Digital Volume Correlation (P-DVC) algorithm that estimates the space/time displacement field, with a “frozen” microstructure and shape of the sample. Additionally, this procedure is combined with a multi-scale approach that is essential for a proper separation between motion and microstructure. A proof-of-concept of the validity and performance of this approach is proposed based on two virtual examples. The studied cases involve a small number of projections, large strains, up to 25%, and noise.
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35
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Rossmann FM, Beeby M. Insights into the evolution of bacterial flagellar motors from high-throughput in situ electron cryotomography and subtomogram averaging. Acta Crystallogr D Struct Biol 2018; 74:585-594. [PMID: 29872008 PMCID: PMC6096493 DOI: 10.1107/s2059798318007945] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 05/29/2018] [Indexed: 12/29/2022] Open
Abstract
In situ structural information on molecular machines can be invaluable in understanding their assembly, mechanism and evolution. Here, the use of electron cryotomography (ECT) to obtain significant insights into how an archetypal molecular machine, the bacterial flagellar motor, functions and how it has evolved is described. Over the last decade, studies using a high-throughput, medium-resolution ECT approach combined with genetics, phylogenetic reconstruction and phenotypic analysis have revealed surprising structural diversity in flagellar motors. Variations in the size and the number of torque-generating proteins in the motor visualized for the first time using ECT has shown that these variations have enabled bacteria to adapt their swimming torque to the environment. Much of the structural diversity can be explained in terms of scaffold structures that facilitate the incorporation of additional motor proteins, and more recent studies have begun to infer evolutionary pathways to higher torque-producing motors. This review seeks to highlight how the emerging power of ECT has enabled the inference of ancestral states from various bacterial species towards understanding how, and `why', flagellar motors have evolved from an ancestral motor to a diversity of variants with adapted or modified functions.
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Affiliation(s)
- Florian M. Rossmann
- Department of Life Sciences, Imperial College London, London SW7 2AZ, England
| | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London SW7 2AZ, England
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